Sunday, January 10, 2010

500kHz brain storming

Being a part of the early access experimenters group, I am in urgent need of ideas how to become QRV on 500kHz.

Receiving seems no issue: SDR using a 2.048MHz LO (produces a center frequency of 512kHz. Alternatively 4.096MHz and an additional divider... There is an 2.097152MHz oscillator available (Reichelt). Dropping this in the box73 SDR will result in a center of 524.3kHz, well in range with 96k sampling.
RX antenna should also be no deal at all, E-probe etc.

How to transmit?? Hmmm, maybe mixing two standard crystals 2.000MHz and 2.500MHz. Yep, that could be the source. 2.500MHz modulated Pierce, so we get a frequency somewhat higher, and the 2.000MHz as VXO for setting the QRG, pulled down, so less is subtracted. This should get me into the 501-504kHz regime.

Found an idea on the internet, 4.000MHz crystal, divide by 8. This will mean to pull the oscillator between 4.008 and 4.032MHz, now THAT is ambitious.

Now fetching the book "LF Today" from the shelf. Will now read the parts which I skipped in the first place.

Ideas welcome, just send me an email!